Torque motor valve actuators are used in myriad systems and environments. For example, many engine air valves associated with an aircraft gas turbine engine are controlled using torque motor valve actuators. No matter the specific end-use system and environment, a conventional torque motor valve actuator includes a plurality of coils, an armature, and a flapper. The coils are controllably energized to control the rotational position of the armature, which is coupled to a valve element, such as a flapper. By controlling the rotational position of the armature, the position of the flapper relative to one or more fluid outlets is controlled and thus fluid pressure and/or flow to a fluid controlled device is controlled.
In many instances, aircraft engine air valves are mounted near the engine. Due to the relatively high temperatures near the engine, the torque motor valve actuators associated with the engine air valves are remotely mounted. This remote mounting can increase the overall cost and complexity of the system. High temperature environments directly impact the power requirements of the torque motor. As the temperature increases, coil resistance increases resulting in increased power demands and higher internal power dissipation. Moreover, because of the high temperatures, conventional vibration damping sources such as rubber O-rings, etc. cannot be used, or used reliably. If there is no or insufficient damping, the valve assemblies and parts thereof (including a torque motor valve actuator and armature assembly) are subject to vibration-induced stresses and may therefore break during operation.
Hence, there is a need for armature assemblies for torque motor valve actuators that can operate in relatively high temperatures and high vibration environments and can be mounted directly to the air valves. The present invention addresses at least these needs.